Method of and apparatus for proportioning combustible fluids



March 2, 1937. E.- x. SCHMIDT METHOD OF AND APPARATUS FQR PROPORTIONING COMBUST IBLE FLUIDS Filed Dec. 1,. 1933 5 Sheets-Sheet 1 as 5 j NATURAL GAS H0 COKEOVENGAS I I 5005mm 355mm.

' Mar ch 2, 1937. E. x. SCHMIDT METHOD OF AND APPARATUS FOR PROPORTIONING COMBUSTIBLE FLU-IDS Filed Dec. 1, 1955 3 Sheets-Sheet 5 5 ms Mn. 5

Patented Mar. 1937 A I A i I v ITED*JS ATBSL ATE T Q j I:".2,072,384'

METHOD, or. APPARATUS, roa raoronnomc oomnusrmm ramps Edwin x. Schmidt, Whitefish Bay, Wia, assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a

corporation'ot Delaware r i Application December 1.193s; SerlalNo. 700,549 I A Claims. (01. 48-180) This invention relates to improvements in pendentlyvarying the volumetric rates of a mu l-' methods or and apparatus for proportioning comtiplicity of combustible fluid flows to maintain bustible fluids. i a substantially constant a number oi .difierent An objector the invention-is to provide novel characteristics of the composite flow or mixture.

; methods;oi and apparatus mr jointly and/or inr the main and branch conduits being shown in 5 .dividually varying the volumetriqratesof flow. elevation, and a portion oithe pressureresponof avpluralityqoi constituent combustiblefluld siveswitch being shown in section, and flows having unlike qualities or characteristicsv Fig.3. isaschematic and diagrammatic illus-, to rapidly and, accurately compensate for varia-. tration oi! apparatus. quite similar in function to 3' tions, in the quallties or characteristics of the the apparatus shown in Figs. 1 and 2,respective-'1o mixture .thereof; x I ly, but ,having. mechanical means substituted tor Another object is to provide novelmethods of theelectrically operated primary or initialv proand apparatus for- 'Jointly varying the volumetric portioning means of the aforementioned -flg-' 3 rates of a plurality o1 constituent combustible urea-the :main and branch conduits being ll fluid flows to-maintain substantially constant cershown in elevation, .and certain other .partso'! l6 tain characteristics of the composite flow and to. the system being shown in section. 1 independently vary thevolumetric rates oi cer- Referring first to' Fig. 1, thenumeral liidesigtain otsaid constituent combustible fluid flows nates a conduit through which a rich gas (such to maintain substantially constant another charasnatural gas) is adaptedtoflow in the direcacteristic or characteristics or the composite flow. tion indicated by the arrow and li'designates Another. object isto provide novel methods of a relatively larger conduit through which a lean' and apparatusior volumetrically proportioning gas '(such as coke oven gas or water. gas) is a multiplicity of combustible fluids having widely adapted to flow in the "direction indicated by the different and variable characteristics to provide arrow,-said conduits Ill and II being adapted to a combustible mixture thereoiwherein all of said discharge into aiconduit I! in which the rich and characteristics are maintained at substantially lean gases are mixed and through which the mixconstant predetermined values. 1 ture flows to the desired point or points of use 01'. Another object is to provide-novel methods of storage. It may. .be assumed that thelean gasf and apparatus for gas mixing control wherein; flowing in conduit ll, whether coke ovengasor 1 mandwhereby a multiplicity of streams of. gas watergas, has a total heating value of from '500 having certain like and certainunlike orvariable to. 550B.v t. u. per cubic foot, and it may be furcharacteristics are so proportioned automatically ther assumed that a total heating value of 800 as toprovide s gaseous mixturewherein-all of i B. t. u. per. cubic foot is desired for the mixturesaid characteristics-are maintained atsubstanflowing through conduit II. The totalheating g. tially constant.predeterminedvalues. i 5 p. value oi the natural gas flowing in'conduit ill will Another and more speciflc object is to provide; be about 1100 B. t. -u. per cubic i'oot. novel electrical and/or mechanical means oper- An adjustable valve I3 is provided in condui able to accomplish the desirable. results afore l0 and an adjustable valve I4 is provided in .conmentioned.' i i i duit ll ,1 said valves being initially adjusted tov 40 Other objects and advantages of thelnvention so proportion vthe volumetric'rates' of said con- 40 will hereinafter appear. 1 f stituent flows as to provide a mixture in conduit The accompanying drawings-illustrate certain H of predeterminedv total heating value, say embodiments of the'inventlon which will now be 800 B. t. u. per cubic foot. It is necessary to described, it being understood" that the embodivary the volumetric rate of flow of the fluid mix-v mentsillustrated aresusceptible of modificationv ture through conduit l2 tocompensate for variin certain details of construction and operation ations inxdemand therefor. Accordingly I pro: thereof without departing from the scope oi. the vide means for eflecting Substantially si t c appended-claims: neous adjustments-of the valves l3 and M to .In the drawings, Figure 1 is a schematic and vary the volumetric rate of fiow of the fluid mixdiagrammatic illustration of. apparatus for proture through conduit I2 as required,.whilemain- 50 portioning combustible fluids,- the main and" taining substantially constant the aforemenbranch conduits being shown inrelevation, with tioned volumetric proportionality between the portions of. the latter broken away. y ratesof flow of the constituent fluids through Fig. 2 is a'schematic and-diagrammatic illus' conduits i0 and ii respectively.

tration of apparatus for jointly and/or inde- Bald means as shown may comprise a well 5 to pressure conditions within the latter.

switch may be adjusted in a known manner to provide for maintenance of the contaotor I5 in an intermediate or neutral position, as illustrated, so long as the pressure of fluid within conduit l2 remains at the preselected value. However, assuming an increase in the rate of demand for the fluid mixture the pressure of fiuid in conduit 12 will drop, with consequent movement of contaotor l5 into engagement with a stationary contact I5,--thus completing an energizing circuit for a motor 16 of the split field reversible type. Said circuit may be traced from line L of a suitable source of electric current by conductor l1, contaotor l5 and contact |5, conductor l8 through one of the field windings of motor l6 and by conductor l9 to line L.

Motor i6 is adapted, through suitable speed reducing gearing I6, to drive a worm 20 which meshes with a gearsegment 2| carried by one arm 22 of the actuating lever attached to valve H. The other arm 23. of said lever carries, in" insulated relation thereto, a rheostat contaotor 24 which cooperatively engages the resistor 25. Contactor 24 is connected by "conductor 26-with one terminal of the operating coil 21 of a polarized relay having a movable contaotor 21 and oppositely arranged stationary contacts 21 and 21 Theother terminal of the coil 21 is connected by conductor 28 with the contaotor 29 of a second rheostat, the resistor of whichis designated by the numeral 30. Said'rheostats 25 and'30 and said relay coil 21 are'arranged in the form of a Wheatstone bridge, the bridge circuit being supplied with direct current from any suitable source, as, for instance, the battery 3|. One

terminal of. battery 3| is connected to the bridge circuit through the contaotor 32 of a third rheostat the resistor of which is designated by the numeral 33,said resistor 33 being' connected at its respective ends with the left-hand terminals of resistors25 and 30. v

Thus it may be assumed that with the three rheostat contactors 24, 29 and 32 in the'positions thereof illustrated the Wheatstone'bridge circuit will be balanced-thus permitting the polarized relay contaotor 21 to remain in the neutral position thereof illustrated. "However, upon operation. of motor Hi to effect opening of 'valve I4 in the manner aforedescribed, the contaotor 24 will be correspondingly moved toward the right, thus.

unbalancing the bridge circuit, with aconsequent flow of current through coil 21 ina direction toeflect engagement of the relay contaotor 21 with, say, contaotor 21 This completes an energizing circuit for a second motor 34 of the split-field reversible. type; said circuit extending fromline L by conductor 35 through relay'contactor 21 and contact 21, by conductor 36 through one of the field windings oi motor 34, and by conductor 31 to line L 1 Motor 34 is connected, througli'suitabie speed reducing gearing 38, with a worm 39' which meshes with the gear segment 40 carried by one arml I, of the actuatinglever for valve I3. Under the conditions assumed the motor 34 will be operated in a direction toefiect opening movement of valve l3,-it being noted that rheostat contactor 29 is carried by but insulated from the other arm 42 of said actuating'lever, wherefore said contaotor 29 is correspondingly moved toward the right to effect a re-balancing oi the bridge coil 21 and movement of contaotor 21 out of engagement with contact 21 to interrupt the aforedescribed energizing circuit of motor 34. Due to the simultaneous and proportional movement of valves l4 and 13 the volumetric proportionality of the constituent fluid flows through conduits I I and I0 is maintained substantially constant,under conditions ofvariation in said rates of flow jointly to compensate for variations in the rate of demand for the mixture.

The manner of operation of the aforedescribed parts in the event of a decrease in the rate oi demand forthe mixture will be readily understood from the foregoing description. Under the con-' ditions last mentioned the contaotor l5 of pressure switch l5'will be engaged'with contact l5 thus completing an energizing circuit for motor 16 which may be traced from line L by conductor 11 through said contaotor l5 and contact 15 by conductor 43 through the other field winding of motor 16, and by conductorllto line L.

; Motor 16 is thus operated in a reverse direction to effect a gradual closing movement of valve |4,--the contaotor 24 being simultaneously moved toward the left across rheostat resistor 25 to 'unbalance the Wheatstone bridge circuit in a sense opposite to that aforedescribed. Consequently current will flow through the'polarlzed relay'coil 21 in a direction to cause engagement of the relay contaotor 21 with contact 21. r

A reverse circuit is thus provided for motor 34, said circuit extending from line L by conductor 35 through'said relay contactor 21 and contact 21, by conductor 44 through the other field winding of motor 34, and by conductor 31 to line 1?. Motors l6 and34 will be operated in the reverse directions thereof last described pending restoration of the desired or required pressure conditions in conduit |2,"the circuit of motor 16 being then interrupted due to disengagement of the pressure switch contactorl 5 from thecontact li and the circuit of motor 34 being interrupted through disengagement of the polarized relay contaotor 21 from; contact 21 due to re-balancing of the Wheatstone bridge circuit.

In practice it is found that either or both of the constituent fiuidsflowing in conduits l0 and Due to the fact that the constituent fluids flow ing in conduits l0 and I! are of substantially different quality with respect to each other, it

will be apparent that an increase in the instantaneous total heating value-per unit volume or the mixture flowing in conduit l2.with respect to a preselected value may be compensated for or corrected by'decreasing the volumetric rate of flow of the rich. gas constituent'afiowing incone I duit H) or by increasing the volumetric rate of flow of theulean gas. constituent flowing inconduit ll,

or--both. Similarly a decrease in .the *instan 'taneous'total heating value per unit volume of the mixture in conduit. 12, with respect to said predetermined value may. be compensatedfor or correctedrby increasing the volumetric rate of flow;

of the rich gas or by decreasing the volumetric rate of flow of. the lean gas,. or both.

In accordance with my invention it is preferred to vary only the volumetric rateof flow of .the rich gas in conduit ID to. compensate for any and all variationsinthe instantaneous. total heat- 'ingvalue perunitvolume of .themixture, since 3 only a relatively small variation'inv the volumetric ratev of flow ,of e the rich. gas will be required to.

compensate forany given variation in the instantaneous total heating value per unit volume of the mixture.

This arrangement desirable for several reasons. For instance, itminimizes variations in the volumetric rateofflowof the mixture through conduit I! as anincident to variations in said total heating value per unit volume. thereof.

Moreover, thegcaiorimeter device employed is naturally more rapidly responsive to variations-in therate of flow of the rich gas constituentv of the mixture than to a corresponding variation in flow of thelean. gas con thevolumetric rate of st tuent- Accordingly l employ a precision type calori meter which is herein shown diagrammatically and designated by the reference-numeral 45. Said calorimeter may be of the character described and claimedinthePackard Patent No. 1,625,277,

dated April 19, 1927, or'the. same maybe of the quick-acting typedescribed and claimed mm'y' co-pending. application Serial I No. J 540,863, flled May- 29, 1931. A continuous sampleo'f the gas mixture flowing in conduit I2 is withdrawn by or supplied tothe-calorimeter.45 through piping 46, 41; suitable means such asthe pressure-regulating valve being provided to,insure'frnjaintenance of the sample at'a predetermined relatively low and substantially. constant pressure.

The calorimeter acts in'a wellknownmanner to ascertain and indicate the total heating value per unit volume of the mixture. flowing through conduit PAL-thev indicator being shown diagrammaticaily at 45, and the same having associated therewith and movable thereby a contactor 45k Contactor 45 is arranged to provide for intermediate or neutral positioning thereof as illustrated so long as the total heating value per unit volume of the mixture remains constant at a value preselected therefor.

Upon an increase'in saidtotal heating value per unit volumel'contactor 45 is 'automatically moved intoeng'agement with a cooperating stationary contact, say, contact 45, thus completing an energizing circuit for a third motor 49 of the split field' reversingfltype; said circuit exing the bridge circuit in a sense which will'cause engagementof'thepolarized relay contactor 21F] with. contact 219, withresultant operation of mo:- tor 34 in a direction to. effect gradual closing j movement-of valve 13. This decr'easesthe volumetricratio of therichgas flowlthrough conduit III with respect to the lean gas flow .through conduit ll, wherefore {the totalheating valueper unit volume of the mixture flowing through con:-

duiti -l l-is reduced..

When the valve I3 has been closed to a degree sufllcient to restore the preselected total heating value per unit volume of the mixture flowing in conduit v I2, the contactor 45 will be moved auto-.

maticallyto the neutral position illustrated, thus interrupting the aforedescribed circuitof motor 49 toprevent' any further unbalancing of the 3 bridge circuit, and the aforedescribed operation;

of motor- 34ml" closingvalve l3 will beinterrupted.v through disengagement of relay contactor 2'1 from contact 2'! .due'to balancing of the bridge,

circuit; As aforeindicated the calorimeter 45 is shown more or less diagrammatically, and it is to be understoodthat in practice the contactor45 and contact 45 (oi-contacts in series therewith) will preferablybeengagedanddiscngaged intermittently to effect closing movement of valve I 3 in steps,- A whereby" over-adjustment and/or hunting of. the control elements is efiectively prevented.

.Inthe event that the total heating value per unit volume. ofthe mixture in conduit 12 falls below the value preselected therefor, the calorimeter contactor 45 will be engaged with contact 45 ,-thus completing a reverse circuit for motor 49, which. circuit may be traced from line L by conductor 50 through contactor 45 and contact 45 by conductor 56 through. the other field. winding of motor 49, and by conductor 52 toline L Motor 49 thereupon operates to effectgradual movement of rheostat contactor 32 toward the 'right'to correspondingly unbalance thebridge circuit in a sense opposite to that last described.

Thereupon the relay contactor 21* is engaged with contact 21 to complete the aforedescribed alternative energizing circuit of motor 34 to effect gradualopening movement of valve [3.

The resulting increa's'ein the volumetric rate of flow of the rich gas will restore the total heat ing. value per unit volume preselected for said mixture, whereupon the calorimeter contactor 45 will be disengaged from contact 45*, with consequent substantially simultaneous interruption of operation of motors 49 and 34 as aforedescribed.

The control elements aforedescribed thus op erate in a simple and eflicient mannerto main+ tain substantially constant the total heating value per unit volume of the mixture inconduit' l2 under conditions of variation in'the volumetric rate of flow of said mixture due to variations in the demand therefor, and under conditions of variation in the total heating value per unit vol-- ume of either or both of the constituent com- .bustible fluid flows in conduits l0 and i l.

, In'the gas mixing control system illustratedin Fig. 2 I prefer to employ a multiplicity of branch conduits 51, 58, 59 and 6|! through which different combustible gaseous fluids are adapted to flow, said branch conduits being adapted to discharge into'a conduit 6| in which the constituent gases are mixed and through which the mixture is conveyed to a point or points of use or storage. Inpractice the conduits 58 and 59 may be of substantially the same sizeor diameter, ,whereas.

conduit 51 preferably of substantially smaller thansaid conduits 58 and 59.1 I prefer to supply through conduit 5'! a continuous stream oihydrogen,-the volumetric rate of flow of said hydrogen being varied in the manner hereinafter described to compensate for certain variations in the flame characteristics of the gaseous mixture, such as flame velocity of flame propagation. r

I prefer to supply through conduit 58 a continuous stream of natural gas,-the same having a relatively high total heating value per unit volume, say, 1100 B. t. u. per cubic foot, and a specific gravity of approximately .65. Water gas is supplied through conduit 59, -the same having a relatively low' total heating value per" unit volume, say, 500 B;-t. u. per cubic'foot, and aspeciflc gravity of .65, that is, substantially the same as the specific gravity of the natural gas. Coke oven .gas is supplied the same having a total heating value volume substantially equal to'that of the water gas, say, 500 B. t. u. per cubic foot, and a speciflc gravity of .35, which is much lower than the through gearing 65, 65 to effect opening move.-

spectiflc gravity of the water gas.

Said conduits 51 to 60 are respectively provided with valves shown in dotted lines at 51, ll", 59', and 60?; and said valves are initially adjusted in any suitable manner, depending upon the instantaneous values of the various characteristics of the constituent fluids, to provide a flowing mixture in conduit 6| having approximately the ideal or desired characteristics; namely, a-preselected or desired total heating value per unit volumeta preselected or desired speciflc gravity;

desired characteristics of flame and/or velocity preselected or temperature, flame length flame propagation; and a preselected or desired volumetric rate of flow of the mixture to satisfy the instantaneous rate of demand therefor.

The valves 51', 58", 59, and 50* areadapted to be driven individually by split-field reversible electric motors 82 to 65, respectively, through the medium of reducing gears designated by the numerals 62', 63", 64", and 65*, andworm andpinion gearing designated by the numerals 82 63 64 and 65'. II the aforementioned desired or preselected characteristics of the fluid mixture, and the rate of demand therefor, remain constant the proportioning and controlling elements now to be described will be unaffected and the several valves 51' to 60, inclusive, will remain in the positions thereof to which they were initially adjusted.

As will be understood, of course, when the rate of demand for the fluid mixture increases or decreases it is desired thatthe volumetric rates of flow of the constituent fluids shall be varied substantially simultaneously and in a manner to maintain the predetermined proportionality therebetween, whereby any unnecessary variation in the values of the aforementioned character'- istics of the mixture is avoided.

For accomplishment of this desirable result I utilize the valve till in conduit 80 as a sort of master" valve; the same having associated therewith a well known form of pressure responsive switch designated in general by the numeral 66, the same comprising a flexible member or diaphragm (i6 the lower surfaceof which is sub- .iected, through piping 66 to pressure conditions on the upstream side of valve till and the upper surface of which is subjected, through piping 86, ta pres'sure conditions on the downstream side of temperature, flame length and/or through conduit 50,--

per unit 2,072,884 size and conduit 60 is of substantially larger'size said valve (or, in other words, to the pressure conditions within conduit i) Said switch is provided with a movable contactor 86 and upper and lower stationary contacts 66 and 66 Switch 66 is thus adaptedto control the operating motor of valve iii) in a manner'to maintain a predeterminedpressure drop across the latter,-said switch 56 having means, such as the adjustable spring 66 whereby the value of said pressure dropmay be varied at will. I,

In" operation, upon an increase in the demand for the fluid mixture, the pressure at the downstream side of valve 60" will decrease thus increasing the'pressure drop across the latter. COD! sequently the diaphragm 66* will be moved upwardly and the coritactor fili controlled thereby will engage contact 85, thus completing an energizing circuit for motor 85,-which circuit may betraced from line L by conductors 61 and 68 through said contactor 68 and contact 66,by conductor 88 through one of the field windings of motor 65, and by conductor to line L' 'Under these conditions motor 65 operates,

ment of valve 50, whereby the-volumetric rate of flow of coke oven gas through conduit 60 is gradually increased. Associated with valve 80' and operable in a direction and to adegree corresponding tothe movement thereof are three rheostat contactors II, 12 and I3,-said contac-' tors being respectively cooperable with resistors ll, 12, and Il One terminal of resistor 1| is connected by conductor I4 with one terminal of a resistor with which the contactor 15 is adapted to cooperate,the other terminal of resistor 1i being con nectedby' conductor 15 with one terminal of a resistor 11} with-which the contactor 11 is adapted to cooperate, the other terminals of resistors l5 and 11 being connected by conductor 18. Contactor II is connected by conductorlfl with one terminalof the coil of a polarised relay,- the other terminal of said'coil being connected by conductor M with contactor l1.

As will be understood the resistors I l 15', 1!

sult the polarized relay contactor 80* will be moved into engagement with one of the stationary contacts, say, contact 80 thus completing an energizing circuit tor 'motor 6l, which circuit may be traced from line L by conductors 61 and 83 through said contactor 80" and contact 80*, by conductor 84 through one of the windings of motor 64, and by conductors 85 and 10 to line L. Motor 64 thus acts, through gearing 64 64 to effect gradual'opening movement of valve 59 ,-the contactor 11 moving along with valve 59 and cooperating with resistor 11' to gradually effect re-balancing of the bridge.

In like manner theresistor 12 and'contactor 12, have associated therewith in the form of a Wheatstone bridge circuit the resistor 85' and contactor 85, the resistor 86 and contactor -86;

the polarizedrelay will engage contact 91 thus" completing an obvious circuit for motor 53 whereby the latter is operated to effect, through gearing 63, 63 opening movement of valve 58*;to a

degree corresponding with the degree of opening of the mixture inconduitiil with respect -to-a movement of valve 60".

So also the resistor I3 an'd contactor 13 have associated therewith in the form'of a Wheatstone bridge circuit the resistor 90 and contactor- 99, the resistor 9l and contactor 9|,and thep'olarized relay coil 92,--the latter having associated therewith the movable contactor 92 and stationary contacts 92', 92, and abattery 93 being connected between contactor '90 and a conductor 93 as described incon'nection with the first mentioned bridge circuit. ized relay will engage contact 92 thus completing an obvious circuit for motor Blwhereby the latter is operated to effect, through gearing 52 62' opening movement of valve 51 to a degree corresponding with the degree of opening movement of valve 60%. g

The means aforedescribed thus provides for substantially simultaneous opening'movement of v allof the valves 60 59, 58% and'51 to like degrees to increase-the volumetric rate of flow of the mixturethrough conduit 6| to satisfy the increased demand for the mixture. Inasmuch as the relative volumetric proportionality of the con stituent'fluid' flows is maintained substantially constant under such conditions it will be apparent that substantiallyno change is-efiected in the total heating value per unit volume or other qualities or characteristics 'of 1 the mixture. When the volumetric rate of flow of the mixture has been {increased to the required extent, the pressure switch 66 is operable automatically. to interrupt the circuit of motor 65 whereby opening movement of valve Gilis discontinued. Due to re-balancing of the bridge circuits included in the respective controls'of valves 59, 58 and 51 opening movement of said valves will likewise be discontinued.

The operation of the control elements in the event of a decrease in the rate of demand for the mixture in conduit 6| will be more or less ap-.

parent fromthe foregoing description. Due to building up of pressure on the downstream side of valve 60 under these conditions, the pressure drop across the latter will decrease below the.

value preselected therefor by the adjustment of spring 66 and the contactor of switch 66 will be engaged with contact 65.

This completes a circuit for motor 65 to efiect operation thereof in a direction the reverse of that aforedescribed,

said circuit extending, from line L by conductors Gland 68 through contactor Gii and contact 66 by conductor 94 throughthe other winding of motor 55, and by conductor ill to line L Valveill will thusbe gradually moved toward closed position, -.-the rheostat contactors ll, 12 and 13 being simultaneously moved in. a counterclockwise direction to effect unbalancin'g of the bridge circuits respectively controlling operation of motors 64, 63 and 62. That is to say, the contactors 81* and92 of thepolarized relays will be engaged with'the contacts 89, 81 and Contactor 92 of the polar- 92, thus completing-reverse. circuits for said motors to effect gradual closing movement ofvalves 59, 58 and 51:.

When the volumetric-rate of flow of the mixture hasbeen reduced to the required value the pressure-switch contactor 65 will be moved to j neutral position to interrupt the-energizingv cir ruption of operation of motors 64, 63, and 52 In order to compensatefor, any increase or decrease in the total. heating value per unit volume.

desired or preselected value, say, 800 B. t. u.' per,

cubic foot, I provide a'calorimeterli which may be and preferably is of the character described in connection with the control system of Fig. 1, and the parts thereof are given like numerals of reference.

mixture in conduit 6| with respect to the value preselected therefor by the settingof the calorimeter parts, the contactor 45 is moved into en- 'gagementwith. contact 45, thus completing an energizing circuit for a motor 95 of the splitfleld reversingtype; said circuit extending from line L by conductors 96,91 and 98 through contactor 45 and contact. 45; by conductor 99 through one field of said motor 95, and by conductors I and)! to line L".

Motor thus operates in a direction to effect, through gearing'95, 95 movement (say, (10W!!! ward movement) of contactor 85 over resistor 85. This unbalancesv the Wheatstone bridge cir cuit including the polarized relay coil 81 in a sense to cause engagement of contactor 81 with contact 8'l thus completing the aforedescribed energizing circuit of motor 63 which effects move-'- ment of valve 58 towardclosed position. It will be noted that valve 58?.under these conditions is operable independently of all of the other valves, and inasmuch as the adjustment is made in the volumetric rate of flow of the natural gas,+which has a very high total heatingvalue per unit volume, it will be apparent that only avery small movementlof valve 58 will ordinarily be required to restore the desired total heating value per unit volume of the mixture.

Similarly in the event of a decrease in the total heating value per unit volume of the mixture, the calorimeter contactor 45' will be. en-

gaged temporarily with contact 45 to effect a reverse operation of motors 95 and.63 whereby valve 58 is graduallymoved toward closed position in an obvious manner to restore the desired quality of the mixture;

Ordinarily any. such necessary change in the volumetric rate of flow of natural gas through conduit 58 will be of such small degree as to leave the volumetric rate of fiow of-the mixture in conduit 6| substantially unafiected. However, it is to be understood that the pressure-switch 66 and the control elements associated therewith are at designated in general by the numeral I02; said meter being supplied throughpiping I93 and I and pressure-regulating valve J05 with a o Thus. assuming even a very slight increase in 2 the total heating value per unit volume of the selected therefor by the setting of meter I02, the

contactor I02 will be engaged with contact I02, thus completing an energizing circuit for the split-field reversible motor 'I 06, which circuit may be traced from line L by conductors 96 and I0! through contactor I02 and contact I02", by conductor I08 through one field of said motor I06,

and by conductors I09 and IOI to line L.

, Motor I06 thus operates in a direction to effect, through gearing I06, I06", movement (say, downward movement) of contactor I5 over resistor 15. This unbalances the Wheatstone bridge circuit including the polarized relay coil 00 in a sense to cause engagement of contactor with contact 80, thus completing the aforedescribed energizing circuit of motor 64 which effects movement of valve 59 toward closed posi-- tion.

It will be noted that valve 59 under these conditions is operable independently of all of the other valves, and inasmuchas the adjustment is made in the volumetric rate of flow of the water gas,-which has a relatively low total heating value per unit volume (as compared with the natural gasin conduit 58) and a relatively high I gravity (as compared with the coke oven gas in conduit 60), it will be apparent that only a. very small movement of valve 59 required to restore the desired value of the specific gravity of the mixture, whereas the change in the total heating value per unit volume of the mixtureas an incident to such movement will be comparatively small.

Similarly in the event of a decrease in the specific gravity of the mixture, the-meter contactor I 02 will be engaged temporarily with contact I02 to effect a reverse operation of motors I06 and 64 whereby valve toward closed position in an obvious manner to restore the desired specific gravity of the mixture." Any necessary adjustment ofvalve'59e individually in the manner just described to restore the preselected specific gravity of the mixture will thus have only a comparatively small effect upon the volumetric rate of flow of the mixture; but as aforestated the pressure-switch 66 and the control elements the volumetric rate of fiowof the mixture is maintained substantially constant.

In order to maintain at a substantially constant predeterminedvalue the flame temperature.

and other desiredflame characteristics of the mixture in conduit 6| I provide means for individually adjusting the position of valve 5'! whereby the volumetric rate of flowof the hydrogen is varied. Said means may comprise a Bunsen burner or jet burner'of the character illustrated will ordinarily be 59 is gradually moved a ociated therewith l will of course function when necessary .to effect f joint operation of the several valves, whereby couple I I Shaving its hot-junction subjected to" the temperature of the flame at the normal tip of the inner cone II4.

Thermo-couples H5 and IIS are connected in series with each other between the lower terminal of a glavanometer coil II! and the adjustable contactor II8 associated with a resistor H8. The upper terminal of coil Ill and the left-hand terminal of resistor 8' are connected in common by conductor HQ with one terminal of a battery I20,the other terminal of said bat-' tery being connected through an adjustable rheostat I2I with the right-hand terminal of resistor H8. Rheostat I2I,is adapted to be initially adjusted manually to control the value of current flowing from said battery,-and.the same may be thereafter adjusted at intervals to compensate for decrease in strength. of the battery current ;as an incident to ccntlnued'use thereof.

Contactor H8 is initially adjustable manually to effect .neutral or intermediate positioningof the galvanometer needle, when the flame temperature, flame length, and other desired characteristics of the flame at burner IIO are of the desired or required value. Needle III carries a contactor II'I which is cooperable with the stationary contacts III and H1 selectively.

The arrangementof the parts just described is such that under normal conditions (that is, when the flame characteristics are of the desired values) the currentgenerated in the thermocouples H5, Illwill be equal to and opposed to the battery currentwhich tends to traverse the coil 1, wherefore the contactor II'I. will be permitted to assume theintermediate or neutral position thereof illustrated.

On the other hand, if it be assumedthat the flame temperature, for instance, increases with respect to the value preselected therefor, the

unbalancing of the circuit of coil III in a sense to cause engagement of contactor I I'I with, say, contact II'I. This will complete a circuit for a split-field reversible motor I22 which, through gearing I22, I22 is adapted to drive the contactor associated with resistor 90. Said circuit may be traced from line L by conductors 9B and I23 through contactor III and contact II'I, conductor I24 through one field of said motor I22, and by conductor I25 to line L.

Under these conditions it may be assumed that motor I22 is operated in a direction to effect downward movement of contactor 90 over resistor 90, thus unbalancing the bridge circuit including coil 92 in a sense to effect engagement of, the polarized relay contactor 92 with contact 92 This completes a circuit for motor 62 to effect operation thereof ,ina direction to cause gradual closing movement of valve 51, thus reducing the volumetric rate of supply of hydrogen to correspondingly decrease the flame temperature and other related flame characteristics of the mixture supplied to burner IIO.

'When the preselected flame temperature has been restored contactor II'I will be moved 'automatically to neutral position, thus interrupting the'aforedescribed circuit of motor I22, and due to balancing of the bridge circuit including coil 92 the contactor 82 will be disengaged from contact 92 to interrupt the aforedescribed circuit of motor 62.

Assuming a decrease in the flame temperature with respect to the preselected value, the galvanometer III will be operatedautomatically to at one end thereof with a piston I32 which is slideffect engagement of contactor H1 with contact Ill! whereby a reverse circuitis provided I stantially like the systems illustrated in Figs. 1,

for motor I22,-said circuit extending from line L by conductors 96 and-I23 through contactor H1 and contact II F, by conductor I26 through the other. winding of motor I22,and'by conductor- I25 to line L. 1

Accordingly contractor 98 will be moved upwardly over resistor 98! to unbalance, in the opposite sense from that aforedescribed, the bridge circuit including 'coil 92. ing engagement. of contactor 92* with contact 92 will complete an obvious circuit for motor 82 wherebythelatter is operated in adirection to efiect gradual opening movement of valve 51?. When the desired value of flame temperature has been restored contactor II1 will again be per-; mitted to assume its neutral position, with the;

the art, an increase or a decrease in the flame" length at burner II8 will affect the position of results aforeindicated. .1 As will be understood by those skilled in the galvanometer contactor H1 in substantially the manner described in connection with an increase or decrease j in flame temperature.- Similarly any increase or decrease in the velocity A oi flame propagation will have a corresponding effect upon the value oi. the flame temperature or the flame length.

Any one or more of these flame characteristics may be very important m a givenginstallationi Thus, if the gas mixture is to be used for heatheating a furnace ora group of furnaces, a constant value of the flame temperature may be considered of primary importancer-whereas for v a process of making electric lamps both the flame length and the flame temperature must be maintained substantially constant in order to obtain the best results, I

The proportioning and mixing control systemv illustrated in Fig. 3 is in certain respects subin the Wiinch Patent No, 1,558,529, dated Octo -I ber 27, 1925. l

Thus I prefer to employ a branch conduit I21 through which a continuous stream of water gas,

having a total heating value of about 500 B. t. u.

per cubic foot and a specific gravity of about .65.:

is adapted to flow; a branch conduit I28 of, like size through which natural gas, having a total heating value of about 1100 B. t. u. per cubicfoot and a specific gravity of about .65, is adapted to flow; and a branchconduit I29 of relatively larger size through which coke oven gas, having a total heating value of about 500 B. t. 11. per' cubic foot and a specific gravity of about .35, is

adapted to flow. Conduits I21, I28 and I29 joint,- ly discharge into a relatively largeconduit I38 in which the constituent gaseous fluids are mixed and through which theimixture is conveyed to a point or points of use or storage.

Conduits I21, I28, and I29 are respectively pro vided with adjustable valves I21, I28, and

I29 ,--said valves having like angular positions within said conduits and the same being operable jointly under given conditions through the medium of a rod or link I'3I. Rod I3I is provided The result- V able within a. closed cylinder I33.,

Communicating with said cylinder I33." above and below piston I32 are a pair of small pipes I34 and I35 the outer ends of which are arranged very closely adjacent to each other and exposed at the inner surface of the end wall of a closed chambercr container I36. 'Pivotallyrmounted within chamber. I36 is a pipe ornozzle I31 which is supplied through pipe I31 with oil or other liquid under pressure or compressed gas from any suitable .source,--the pipe I38 communicating with the compressor or pump (not shown)" to provide for withdrawal andre-use oi oi fluid discharged through pipe I31.

any excess" The angular position oipipe I31 is subject to a pipe I42 afiording communication between the chamber at the upper side of. diaphragm I48 and the conduit I29 at the downstream side of valve I29 ,,and a pipe I43 aflording communication between the' chamber at, the lower side of diaphragm no and the conduit I29 at the upstream side of valve I29, Pipe 113 1 is biased, as by compression spring I44, in a direction to oppose the'i'orce appliedithereto by pin I39,the degreeoi compresslon oisaid springbeing adjustable at will inany well known manner to preselect the value of the pressure drop across valve I29. Thus assuming an increase in demand tor the apparent that the pressure of fluid on the down-1 place nozzle I31 upwardly out of neutral .or balanced relation to the adjacent ends of pipes I34, I35, so that a major portion. or all of the fluid pressure transmitted by said nozzle will traverse pipe I34 and be applied to the upper end of piston I32. Consequently piston I32 will be moved downwardly within cylinder I33 to eflfect opening movement of valve I29,valves I28. and I21 being moved simultaneously in a like direction and to a corresponding degree, due .to the mechanical interconnection provided by the aforementioned rod I 3|. p

The volumetric rates of flow of the constituent combustible fluids arethus rapidly varied simultaneously while maintaining a predetermined volumetric proportionality therebetween, wherejusted positions thereof.

In order to maintain the values of the pressure drops across valves I28 and I21 equal to or definitely proportional to the value of the pressure drop across valve I29, I provide in the respective conduits I28 and I21 the individually operable valves I28 and I21 ,-the same being located in advance of the valves I28 and I 21*, respectively. Means are provided for eflecting adjustment of valve I28 automatically'in reupstream side of valve I29.

spouse to variations in the differential value of the pressure drops across valves I29 and I28; and means are also provided for effecting adjustment of valve I21 automatically in response to variations in the differential value of the pressure drops across valves I29 and I21.

The operating means for valve I28 comprises a rod I44 attached to said valve and to a piston I45 which is slidable within a closed cylinder I46,-pipes I41 and I48 communicating with said cylinder respectively above and below said piston and having the opposite ends thereof arranged closely adjacent to each other at the inner surface of an end wall of a chamber I49. A nozzle I50 is pivotally supported within chamber I49,--and said nozzle is maintained in the intermediate' or neutral position'thereof through the opposingaction of rods I6l and I52 so long as the pressure drops across valves I28 and to each other.

As shown the upper surface of diaphragm I5I is subjected through piping I53, I54 to the pressure at the downstream side of valve I29, and

I28 bear a predetermined ratio or relationship the lower surface of diaphragm I5I is subjected through piping I55, I56 to the pressure at the surface of diaphragm I52 is subjected through piping I51 to the pressure at the downstream side of valve I28, and the upper surfaceof diaphragm I52 is subjected through piping I58 to the pressure at the upstream side of valve I28.

For instance, if the pressure of fluid at the up- 7 stream side of valve I29 should increase for any reason (thus increasing the value of thepressure drop across said valve) diaphragm I5I and rod I5I wll be moved upwardly to effect upward displacement of nozzle I50, thus providing for application of the major portion of the force of fluid from nozzle I50 to the upper end of piston I45 to effect opening movement of valve I28.

This will of course increase the pressure of fluid at the upstream side of valve I28, and when the value of the pressure drop across the latter bears a predetermined ratio to the value of the pressure drop across valve I 29, diaphragm I52 and rod I52 will act automatically, under the influence of the increased pressure at the upstream side of valve I28, to return nozzle I50 to its intermediate or neutral position.

The means for predetermining the ratio of the pressure drops across valves I29 and I28 comprises essentially a disk or abutment I59 carried by. a rod I59,--said disk being interposed between and slidable with respect to nozzle I50 and a rod or plate I59 which is pivoted at the end thereof diagonally opposed to the pivot of nozzle I50. Means are provided for automatically adjusting disk I59 in the manner and for the purpose hereinafter described.

The operating means for valve I21 comprises a rod I60 attached to said valve and to a piston I6I which is slidable within a closed cylinder I62,--pipes I63 and I64 communicating with said cylinder respectively above and below said piston and having the opposite ends thereof arranged closely adjacent to each other at the inner surface of an end wall of a chamber I65. A nozzle I66 is pivotally supported .within chamber I65,-and said nozzle is maintained in the intermediate or neutral position thereof through the opposing action of rods I61 and I68 so long as the pressure drops across valves I29 and I21 bear a predetermined ratio to each other.

As shown the upper surface of diaphragm I61 Similarly the lower is subjected through piping I69, I54 to the pressure at the downstream side of valve I29, and the lower surface of diaphragm I61 is subjected through piping I10, I56 to the pressure at the upstream side of valve I29. Similarly the lower surface of diaphragm I68'is subjected through piping IN to the pressure at the downstream side of valve I21, and the upper surface of diaphragm I68 is subjected through piping I12 to the pressure at the upstream side of valve I21.

In the event of an increase in pressure at the upstream side of valve I29 diaphragm I61 and rod I61 will be moved upwardly to effect upward displacement of nozzle I66, thus effecting opening movement of valve I21, as describedin connection with valve I28 The pressure of fluid at the upstream side of valve I21 will be increased in this manner until the value of the pressure drop across the latter bears a predetermined ratio to the pressure drop across valve I29. whereupon nozzle I66 will be returned automat-v ically to the neutral position illustrated.

valve I21 with respect to the pressure drop across valve I29,--sald disk being carried by a rod I13 and interposed between and slidable with respect to nozzle I66 and a rod or plate I13 which is pivoted at the end thereof diagonally opposed to the pivot of nozzle I66. Means are provided for automatically adjusting disk I13 in the manner and for the purpose hereinafter described.

In order to maintain substantially constant the total heating value per unit volume of the mixture flowing in conduit I30 I provide means for varying the volumetric rate of flow of one of the constituent fluids with respect to other of the same. 1 Moreover, for this purpose I prefer to vary individually the volumetric rate of flow of the natural gas through conduit I28, since because of its relatively high total heating value per unit volume only very small changes in the rate of flow thereof are required to'compensate for such variations in the total heating value of the mixture flowing in conduit I30 as are met with in practice.

This arrangement has the further advantage of minimizing the variations in the volumetric rate of flow of the mixture through conduit I30 as anincident to compensation for variations in the total heating value per unit volume of the latter. Thus I have shown more or less diagrammatically a precision calorimeter 45 which may be and preferably is of the character described in connection with the systems of Figs. 1 and 2,-and the corresponding parts of said calorimeter have been given like numerals of reference.

Assuming an increase in the total heating value per unit volume of the mixture in conduit I30 with respect to the value preselected therefor by the setting of the calorimeter parts, the contactor 45 is moved into engagement with contact 45, thus completing an energizing circuit for a motor I14 of the split-field reversing type; said circuit extending from line L by conductors I and I16 through contactor 45 and contact 45, by conductor I11 through one field of said motor I14, and by conductor I18 to line L.

Motor I14 thus operates in a direction to effect, through gearing I19 and rod I59, movement of disk I59 toward the left to permit automatic lowering of nozzle I50 from its neutral position.

applied through pipe I48 to the lower face of piston I 45 which is thereupon raised to I effect closing movement of valve I28 When the volumetric, rate of flow of fluid through conduit I28 is decreased sufficiently to restore the preselected total heating value of the mixture in conduit I30 contactor 45 of the calorimeter will bemoved to its neutral position thus interrupting operation of motor I14. Moreover, the aforementioned, adjustment of disk I59 merely varies the. ratio or proportionality of the value of the pressure drop across valve I28 with respect to the value of the pressure dropacross valve I29 Accordingly after the required degree of closure of valve I28 the diaphragms I52 will act in'a obvious manner to effect a return. of nozzle I50 to its intermediate or neutral position. J

In'the event ofa decrease in the totalheating value per unit volume of the mixture flowing in conduit I30 the, calorimeter contactor 45 will engage contact 45 thus completing acircuit to. effect reverse. operation ofimotor I14, 5 Said circuit maybe traced from line L by conductors I15, I16 through contactor I5 and contact 45, by conductor I80 through the other field of said motor I14, and by conductor I18 to line L Consequently disk I58 Willibe moved toward the right said nozzle 'I 50.

to raise nozzle I 50, whereby the major portion of the fluid pressur from said nozzle is applied tothe upper surface of piston I 45 to efiect the required degree of opening movement of. valve I28 ,-the diaphragms I5I I52 thereafter act-.- ing automatically to efiect neutral positioning of Also in order to maintain the specific gravity of the mixture in conduit I30 at a substantially constant predetermined value, I prefer to provide means for individually. varying the volumetric rate of flow of the water gas-through conduit I21. Inasmuch as said water gashas a relatively high specific gravity .(as compared with the specific gravity of the coke oven gas in conduit I29) only relatively slight variations in the volumetric rate of flow of said water gas will be necessary to compensate for such variations in specific gravity 'of said mixture in conduit I30 as will, be met I18 to line L.

with in practice. 4 1

Moreover, due to the relatively low total heat-' ing value per unit volume of, said water gas (as compared with the total heating value per unit volume of the natural gas in conduit I28), the atoremetioned changes in the volumetric rate of flow of water gas will have comparatively little eflect upon the total heating value per unit" v volume of the mixture in conduit I30.

Accordingly I provide a. specific gravity meter I02 which may be of the character described in; connection with Fig. 2,-the parts of which have.

beengiven like numerals of reference. Thus upon an increase in the specific gravity of the fluid in conduit I30 with respect to the value thereof preselected by the' setting of meter I02, the con tactor .I02 will engage, contact I02, thus completing a circuit for a motor I82 .of the split-field I reversing type,said circuit-extending. from line L by conductors I15, I83 through contactor I02 and contact I029, by conductor I84 through one field of motor I82, and' -by conductors I85 and Motor I82 thereupon operates, through gearing I86, I81, to eflect movement of disk I13 toward the left, with consequent loweringof nozzle I66 to effect upward movement of .piston 'IGI, wherebyvalve I21 is moved toward. closed position.

After attainment oftheadjustedratio of the pressure drop across valve I21 with respect to the value of the pressure drop across valve I29, nozzle I66 is moved automatically to its intermediate or neutral position,

Similarly upon a decrease in the specific gravity of the fluid flowingin conduit I30, the meter contactor I 02 will engage contact I02 thus completing a reverse circuit for motor I82,- whichcircuit may be traced from line L by conductors I 15, I88 through contactor I02 and contact I02 by conductor I88 through the other winding of motor I82, and by conductors I85, I18 tolineL V g Y I Motor I82 will therefore operate in a direction toeifect movement of disk I13 toward the right,

' with consequent raising of nozzle I66 and lower-' ing of piston I6I to efiect opening movement of valve I21 When the new ratio of the pressure drop across valve I21 with respect to the pres sure drop across valve I29 has been attained,

nozzle I66 will be moved'automatically toneu-v tralposition through the action of diaphragm: I61e,,I68. 1' i From the foregoing description it will be apparent to those skilled in the art that the system of Fig. 1 may be modified by providing a third branch conduit through which watergas, having a relatively high specific gravity,.is adapted to flow,the volumetric rate of flow thereof being controlled jointly with therat'es of .flow of natural gas andcoke oven gas in accordance with and to c'ompensatefor variations in demand forthe fluid mixture; and the volumetric rate of flow of the water gas being subject toindividual control through the medium of a specific gravity meter.

Similarly the systems of Figs. 1 and 3may be modified in accordance. withmy invention by providing a conduit through which a gas, such as hydrogen, is'adapted to flow, the volumetric rate of flow of hydrogen being normally maintained proportional tothe volumetric rates of flow of the other constituent fluids, under conditions of variation in'the rate oi demand for the mixture, and the volumetric'ra'te of flow of the hydrogen being individually'varied .to compensate for variations in flame temperature, flame length, or velocity of flamepropagationof the fluid mixture.

.As indicated in the several figures of the draw-' ings, the size and arrangement of the reduction gearing interposed in the control of the volumetric rate of flow of the natural gas, or other gas of .relatively hightotal heating value per unit volume, is such that said volumetric rate of flow is adjusted quite rapidly to provide for maintenance of the correct or preselected total heating value. per unit volume of the mixed 'gas, which value should be maintained to within onehalf of one per cent accuracy. 0n the other hand," the adjustment of the volumetric rate of flow of the water gas (or coke oven gas) may be effected quite slowly, since the permissible range of variation in specific gravity of the mixture the art that the invention is readily adaptable for the proportioning of combustible fluids other than gases.

What I claim as new and desire to secure by Letters Patent is: I

1. The method of maintaining substantially constant the values of a plurality of different characteristics, such as the total heating value per unit volume and the specific gravity of a mixture of combustible gaseous fluids, which comprises effecting a multiplicity of initially volper unit volume and the specific gravity, of a inixture of combustible gaseous fluids, which for.

comprises effecting a multiplicity of initially volumetrically' proportioned flows of fluids, combining said flows to provide the mixture, separately and simultaneously ascertainingthe instantaneous values of the aforementioned characteristics of said mixture, individually varying the relative volumetric rates of the respective flows in accordance with-and to compensate for variations' in said instantaneous valuesof said characteristics with respect to the values preselected therefor, and substantially simultaneously vary-' ing the volumetric rates of all of said flows while maintaining the required volumetric proportionality therebetween, to thereby compensate for variations in the degree of pressure of the mixture as determined by the rateof demand there- 3. The method'which comprises effecting a plurality of flows of gaseous fluidswhich substantially differ from each other in character, initially adjusting the volumetric rates of flow of said'fluids and mixing the same to provide a mixture having the desired total heating value per unit volume and the desired specific gravity, varying the volumetric rate of flow of one of said fluids in response to variations in the degree" of pressure of the mixture as determined by the rate of demand therefor, thereafter gradually varying the volumetric rate of flow of another of said fluids in response to variations in the volumetric rate OfLflOW' of said first mentioned fluid to normally'maintain a substantially constant predetermined proportionality between said volumetric rates of flow of said fluids, ascertain: ing the instantaneous value of the specific grav-, ity and the instantaneous total heating value per unit volume of the mixture, and independ ently varying the volumetric rates of flow of a plurality of said fluids in accordance with and to compensate for variations in said instantaneous values with respect to the preselected values.

4. The method of maintaining of substantially constant predetermined values a plurality of different characteristics, such as total heating value per unit volume and specific gravity, of a mixture of combustible gaseous fluids, which comprises effecting a plurality of individual flows of fluids of unlike quality, combining said flows to provide the mixture, initially adjusting the relative volumetric rates of said individual flows to provide said predetermined values of the aforementioned characteristics of the mixture, substantially simultaneously varying the volumetric rates of fiow of all of said constituents while maintaining a predetermined proportion-- ality therebetween to compensate for variations in degree of pressure of the mixture as deter-",' V mined by the rate of demand therefor, and sup- I plementally and individually varying the volumetric rates of a plurality of said individual flows with respect to other of the same in accordance with and to compensate for variations in the values of the aforementioned characteristics of said mixture with respect to said predetermined values.

5. The method which comprises effecting two individual flows of gaseous fluids of substantially equal total heating value per unit volume, the specific gravity of one of said fluids being relatively high and the specific gravity of the other fluid being relatively low, efl'ecting a third individual flow of gaseous fluid of relatively higher quality or total heating value per unit volume than said fluids first mentioned, the specific gravity of said third fluid being substantially equal to the relatively high value aforementioned, proportioning and mixing said individual flows to provide a mixture having'the desired quality or total heating value per unit volume and the desired specific gravity, substantially simultaneously varying the volumetric rates of said three flows in accordance with and to compensate for variations in the degree of pressure of the mixture as determined by the rate of demandtherefor, individually varying the volumetric rate of flow of said third fluid in accordance with and to compensate for variations in the quality or total heating value per unit volume of the mixture with respect to a predetermined value, and individu ally varying the volumetric rate of flow of one of said first mentioned fluids in accordance with and to compensate for variations in the specific gravity of the mixture with respect to a predetermined value:

6. The method which comprises effecting two individual flows of gaseous fluids of substantially equal total heating value per unit volume, the specific gravity of one of said fluids being relatively high and the specific gravity of the other fluid being relatively low, efiecting a third individual flow of gaseous fluid of relatively higher quality or total heating value per unit volume, the specific gravity of said third fluid being substantially equal to the relatively high value aforementioned, effecting a fourth individual flow of gaseous" fluid having predetermined flame charby the rate of demand therefor, individually f varying the volumetric rate of flow of said fourth fluid in accordance with and to compensate for variations in the values of the burning qualities of the mixture with respect to certain predetermined values, individually varying the volumetric rate of flow of said third fluid in accordance with and to compensate for variations in the quality or total heating value perunit. volume of the mixture with respectrto, a predeterminedvalue,

' and individually varying thevolumetric rate-of equal total heating value per unit volume, the

specific gravity -,of, one of said fluids being rela- .i tively highrand the specific gravity of the other fluid being relativelyrlow, eifecting a third flow of gaseous fluid-ofrelatively higher. total heating valueper; unitvolume, the specific gravity of said third fluid beingsubstantially equalto the relatively highvalue aforementioned, effecting a fourth individualfiow of gaseous fluid; having g predtermined flamezcharacteristics when burned,

proportioning'and mixing said individual flows to provide a ,mixture having'the desired total heating value per unit volume, the desiredspecific gravity and the desired burning qualities,

substantially simultaneously and proportionally varying the volumetric rates 'of fiow of all ofsaidfiuids in acordance with and to compensate for variations in the degree of pressure of the mix- .ture as determined by the rate of' demand therefor, individually and relatively slowly varying the volumetricirate of fiowof said. fourth fluid in ac cordance with and to compensate for variations in the values of the burningqualities of the mixture withrespect to the valves preselected therefor, individually and relatively rapidly varying the volumetric rate of flow of said third fluid in accordance with and to compensate for variations in the total heating value per unit volume of the mixture with respect to a predetermined value, and individually and relatively slowly Varying the volumetric rate of-fiow of the first mentioned fluid of relatively high specific gravity in accordance with and; to compensatefor variations in the specific gravity of the mixture with respect to a predetermined value,

8. The method of proportioning and mixing a multiplicity of combustible gases to provide a combustible gaseous mixture whose combustion characteristics are of substantially constant predetermined values, which consists in effecting initially volumetrically proportioned flows of said gases, efiecting, a mixture of said flows, automatically varying thevolumetricrateof flow of one of said gases in accordance with variations in the degree of pressureoi' the mixture as ,deter mined by, rate of demand therefor, thereafter gradually varying the volumetric rates of flow of the other gases to thereby maintain a substantially constant predetermined proportionality between the latter and said first mentioned gas, simultaneously and individually ascertaining the instantaneous total heating value per unit volume, the specific gravity, and the flame characteristics or said mixture, and correspondingly and respectively varying the volumetric rates of fiow of said other gases, whereby the values of said characteristics of said mixture are maintained substantially constant.

9. In a gas mixing and "proportioning control systernjin combination, a multiplicity of branch conduits through which combustible fluids having substantially different combustion characteristics are respectivelyadapted to flow, a main conduit intowhich' said branch conduits are adapted to discharge to provide a combustible mixture, a valve in each of said branchconduits,

said valves being initiallyadjustedto so proportion said flo'wsvolumetrically as to provide a mixture whose combustion characteristics are of predetermined values respectively, means responsiv'e to variations in the degree of pressure of said mixture as determined by the ratejof demand therefor for-effectingproportional admetric rate of flow of the mixture is increased or decreased in accordance with said variations in the degree of pressure thereof, means for con- 'justment of all of said valves whereby thevolutinuously ascertaining the valueof agivencom bustion characteristic of said mixture with respect to a predetermined value, means controlled by said last mentioned means-for effecting adjustment' of one of said valves individually wherebythe value of said combustion characteristic in said mixture is maintained substantially constant, means for continuously ascertaining the value of another given combustion character'- istic of said mixture with respect to a predetermined value, and means'controlled by said last mentioned means for effecting adjustment of another of said valves individually whereby the value of said last mentioned combustion characteristic in said composite-flow is likewise maintained substantially constant.

10. In a device 0fthe character described, in combination, a plurality of branch conduits through which combustible fluids having substantially different combustion characteristics are respectively adapted to flow, a main conduit into which said branch conduits are adapted to discharge and through which the combustible mixture is adapted to flow, a valve in each of saidbranch conduits, a reversible electric driving motor for each of said valves, a switch re"- sponsive to pressure conditions within said main conduit, said switch being adapted to effect operation of one of said motors in a direction to effect closing movement of its associated valve upon a predetermined increasein pressure "in said main conduit and to effect operation of said last mentioned motor in a direction to efiect opening movement of said valve upon a predetermined decrease in pressure in said main conduit, a contactor movable-with said last mentioned valve and a resistance with which said contactor is adapted" to coact, a contactor movablewith the other of said valves and-a resistance with which said lastmentioned contactor is adapted to coact, a polarized relay having a coil, said resistances and said contactors and coil being connected in the form of a'Wheatst'one bridge with respect to a suitable source of enw ergy supply, a contactor associated withsaid relay coil, apairv of contacts to be selectively engaged by said contactor upon unbalancing of said bridge circuit in opposite senses respectively, said contactor and said contacts being adapted to control thedriving motor of'the other of said valves to thereby normally and automatically maintain a. predetermined volumetric proportionality between said constituent fiows, a calorimeter adapted to continuouslyascertain the instantaneous total heating value per unit volume of the mixture flowing in said main conduit, a. reversible electric motor controlled by said calorimeter, a contactor driven by said motor; and a third resistance with which said conta'ctor is adapted to coact, said last mentioned contactor and said resistance being associated with said Wheatstone bridge circuitto provide for unbalancing of the latter in a senseand to a degree depending upon the variation in the total heating value per unit volume of said mixture with respect to a predetermined value, whereby said second. mentioned valve is operated indecharge and through which the mixture of said fluids is adapted to flow, a valve in each of said branch conduits, said valves being initially adjusted to provide in said main conduit a mixture having a predetermined total heating value per unit volume, a predetermined specific gravity and predetermined burning characteristics,pressuremeans responsive to variations in the degree of pressure of said mixture as determined by the rate of demand therefor to automatically eiifect adjustment of one of said valves, means operatively associated with said last mentioned valve to effect substantially simultaneous and proportional adjustment of all of the other valves, whereby the volumetric proportionality of said fluids is maintained substantially constant, calorimetric means for continuously ascertaining the instantaneous total heating'value per unit volume of said mixture, means controlled by said calorimetric means and responsive to variations in said value to effect adjustment 0! one of said other valves individually whereby the total heating value per unit volume of said mixture is maintainedsubstantially constant, means for continuously ascertaining the instantaneous value of the specific gravity of said mixture, means controlledby said last mentioned means and responsive to variations in said value to effect I adjustment of another of said valves individually whereby the specificgravity of saidmixture is maintained substantially constant, means for continuously ascertaining the. instantaneous value of the burning characteristics of said mixyture, and means controlled by said last mentloned means and responsive to variations in .said value to efiect adjustment of still another of said valves individually whereby the valueof the burning characteristics of said mixture is maintained substantially constant. 1

12. In agas mixing and proportioning control system, in combination, a multiplicityof branch conduits through which combustible fluids having substantially different combustion characteristics are respectively adapted to flow, a main conduit into which said branch conduits are adapted to discharge and through which the mixture is adapted to flow, a power operated valve in each of said branch conduits, means responsive to variations in pressure of fluid in said main conduit as an incident to variations in demand for the mixture to automatically effect adjustment of one of said valves, associated means operable automatically toeffect a followup operation of another (if-said valves whereby the volumetric rates of flow of said constituents are normally maintained. substantially proportional to each other, means for continuously ascertaining the instantaneous total heating value per unit volume of said mixture, and

means responsive to variations in said value with respect to a predetermined value to effect corresponding operatlon of said second'mentioned valve individually whereby the total heating value per unit volume of said mixture is maintained substantially constant. A

13. In a control system of the character described, in combination, branch conduits through which hydrogen, natural gas, water gas and coke oven gas are respectively adapted to flow, a main conduit into which said branch conduits are adapted to discharge and through which the resulting gaseous mixture is adapted to fiow, means responsive to variations in the degree of pressure of the mixture. as determined by the rate of demand therefor'to. jointlyand proportionally vary the volumetric rates of flow through said branch'conduits, means responsive to variations in the burning characteristics of said mixture to individually vary the volumetric rate of v flow of hydrogen whereby saidburning characteristics are maintained of substantially constant value,'means responsive to variations in the total heating value per unit volume of said mixture to individually vary the volumetric rate of flow of natural gas whereby said total heating value per unit volume is maintained substantially constant, and means responsive to variations in the specific gravity ofsaid mixture to individually vary the volumetric rate of fiow of water gas whereby said specific gravity is maintained substantially constant.

14. In a controlsystem of the character described, in combinatiombranch conduits through which hydrogen, natural gas, water gas and coke oven gas are respectively adapted to flow, a main conduit into which said. branch conduits are adapted to discharge and throughwhich the resulting gaseous mixture is adapted to flow, means including a valve in each of said branch conduits, said valves being initially adjusted to provide in said mixture predetermined burning characteristics, a predetermined total heating value per unit volume and a predetermined specific gravity, means responsive to variations in pressure of said mixture as an incident to variationsin demand therefor to automatically effect adjustment of the valve in saidbranch conduit through which said coke oven gas is adapted to flow, associated means to automatically effect a corresponding adjustment of each of the other valves whereby the flows through all of said branch conduits are normally maintained substantially proportional to each other under conditions of variation in the rate of demandfor the mixture, means for burning a continuous sample of the mixture to ascertain the instantaneous value of the flame temperature, associated means controlled by said last mentioned means for individually varying the volumetric rate of flow of hydrogen to compensate for variations in said value with respect to a" predetermined value, means including a calorimeter for burning a continuous sample of the mixture to ascertain the total heating value per unit volume thereof, associated means controlled by said calorimeter for individually varying the volumetric rate of flow of natural gas to compensate for variations in said value with respect to a predetermined value, means including a specific gravity meter for continuously ascertaining the specific gravity of said mixture, and associated means controlled by said specific gravity meter for individually varying the volumetric rate of flow of water gas to compensate ,for variations in the value of said specific gravity with respect to a predetermined value.

15. The method of maintaining substantially constant the values of a plurality of diflerent characteristics, such as the total heating value per unit volume and the volumetric rate, of a flowing mixture of combustible gaseous fluids, which comprises effecting a multiplicity of initially volumetrically proportioned flows of the fluids, combining said fluids to provide said flowing mixture, jointly and proportionally varying the volumetric rates of flow of said fluids in accordance with and to compensate for variations in the degree of pressure of the mixture as determined by the rate of demand therefor, and individually varying the volumetric rate of flow of one of said fluids in accordance with and to compensate for variations in the instantaneous total heating value per unit volume of said mix- CERTIFICATE OF CORRECTION. Patent No. 2,072,58h. I March 2, 1957.

EDWIN x. SCHMIDT.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 17, for the word "movement" re'ad movements; page 6, second column, line 6, for "glavanometer" read galvanometer; page 7, first column, line 8, for "contractor" read contactor; page 9, first column, line 15, for "a" before obvious" read an; page ll, first column, line 19, claim 7, for "predtermined" read predetermined; and line 53,- same claim, for

"valves" read values; line 65, claim 8, for "or"read of; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of October, A. D. 1957.

Henry -Van Arsdale. (Seal) Acting Commissioner of Patents. 

